JP6621781B2 - Assembly printed circuit board and printed wiring board manufacturing method - Google Patents

Description

  The present invention relates to an assembly printed board and a method for manufacturing a printed wiring board.

  For example, a printed wiring board having a metal core is known (for example, Patent Document 1).

JP 2012-212951 A

  By the way, a camera module mounted on a high-functional portable terminal such as a smartphone is one of the thickest components. In recent years, with the increasing demand for thinning and lightening mobile terminals, there has been an increasing demand for thinning camera modules.

  Here, since a certain distance is required between the image sensor and the lens, it is necessary to shorten the distance from the upper surface of the image sensor to the bottom of the printed wiring board in order to reduce the thickness of the camera module. is there. One technique for meeting this requirement is to make the printed wiring board thinner.

  However, if the printed wiring board is thinned, the rigidity of the printed wiring board is reduced, so that the mountability of the printed wiring board and the strength as a camera module may be impaired. On the other hand, if the metal core substrate is made of a high-strength metal material in order to ensure the strength of the printed wiring board, the heat conductivity of such a metal material is often low, so the heat generated in the printed wiring board is internal. May accumulate.

  Furthermore, metal materials with high thermal conductivity (especially copper and aluminum) tend to generate burrs during dicing due to the nature of the metal materials. The occurrence of burrs may affect the quality of the printed wiring board.

  An object of the present invention is to provide a structure of a printed wiring board that can suppress the occurrence of burrs when dicing without reducing the strength (rigidity) and thermal conductivity of the printed wiring board.

The collective printed circuit board according to one aspect of the present invention is a collective printed circuit board having a plurality of arrangement areas each provided with a plurality of unit boards and an exposed area that is an area between the adjacent arrangement areas . A main surface and a second main surface which is a surface opposite to the first main surface, and at least one of the first main surface and the second main surface is flat from the arrangement region to the exposed region. and certain metal layer, a metal core substrate having a plated layer provided so as not to overlap with the exposed region in contact with said first main surface and the second major surface of the metal layer, the surface of the metal core substrate And an electrically conductive pattern formed on the insulating layer corresponding to the arrangement region.

  In addition, the problems disclosed by the present application and the solutions thereof will be clarified by the description in the column of the embodiment for carrying out the invention and the description of the drawings.

  According to the present invention, it is possible to obtain a collective printed circuit board that does not easily generate burrs when dicing while ensuring strength even when thin.

It is sectional drawing which shows schematically the aggregate printed circuit board which concerns on this embodiment. It is a top view which shows roughly the collective printed circuit board which concerns on this embodiment. It is sectional drawing which shows the outline when the collective printed circuit board which concerns on this embodiment is diced. It is a top view which shows roughly the collective printed circuit board which concerns on this embodiment. It is a graph which shows the relationship between the ratio of the thickness of the metal layer which comprises a metal core board | substrate, and a plating layer, and the deformation amount of a printed wiring board. It is the schematic which provides a reinforcing fiber sheet in the insulating layer of the assembly printed circuit board concerning this embodiment. It is the schematic explaining the adhesiveness of the plating layer and insulating layer of the collective printed circuit board which concerns on this embodiment. It is a figure explaining the manufacturing method of the collective printed circuit board concerning this embodiment. It is a figure explaining the manufacturing method of the collective printed circuit board concerning this embodiment. It is a figure explaining the manufacturing method of the collective printed circuit board concerning this embodiment. It is a figure explaining the manufacturing method of the collective printed circuit board concerning this embodiment. It is a figure explaining the manufacturing method of the collective printed circuit board concerning this embodiment. It is a figure explaining the manufacturing method of the collective printed circuit board concerning this embodiment. It is a figure explaining the manufacturing method of the collective printed circuit board concerning this embodiment. It is a figure explaining the manufacturing method of the collective printed circuit board concerning this embodiment. It is a figure explaining the manufacturing method of the collective printed circuit board concerning this embodiment. It is a figure explaining the manufacturing method of the collective printed circuit board concerning this embodiment. It is sectional drawing which shows roughly the assembly printed circuit board by which a plating layer is laminated | stacked on the 1st side surface of the metal layer which concerns on other embodiment. It is sectional drawing which shows roughly the assembly printed circuit board in which a part of metal layer which concerns on other embodiment is formed thinly. It is sectional drawing to which the metal layer which has a curved surface on one side was expanded in the collective printed circuit board in which a part of metal layer which concerns on other embodiment is formed thinly. It is sectional drawing to which the metal layer which has a curved surface on both sides is expanded in the collective printed circuit board in which a part of metal layer which concerns on other embodiment is formed thinly. It is sectional drawing which shows roughly the assembly printed circuit board by which a plating layer is laminated | stacked on the 2nd side surface of the metal layer which concerns on other embodiment. It is sectional drawing which shows roughly the assembly printed board formed by laminating | stacking the metal core board | substrate which concerns on other embodiment through an insulating layer. It is sectional drawing which shows roughly the assembly printed circuit board which does not have a plating layer. It is sectional drawing which shows the condition where a burr | flash generate | occur | produces when dicing in the collective printed circuit board which does not have a plating layer.

  Hereinafter, a collective printed circuit board 100 according to an embodiment of the present invention will be described with reference to the drawings as appropriate. Here, the collective printed circuit board 100 is described as being preferably used as the collective printed circuit board 100 for the camera module. For example, an optical module is required to have a small flatness and excellent flatness because it handles light. This is because it is easy to receive light, adjust the optical path of light emission, and the like, and is convenient. In particular, a twin-lens camera module that has recently been spotlighted by a mobile phone is required to have flatness because two image sensors are arranged next to each other on the same substrate. Therefore, the mounting board itself is required to have rigidity. At present, when a plurality of image sensors are arranged in one chip, the flatness of the substrate is required, and the flatness is not changed by heat or the like. Furthermore, even when a plurality of imaging elements are cut and supplied as one chip in the future, the chip itself becomes large, and this also requires rigidity and flatness. In either case, one metal core substrate 110 that can support the plurality of imaging elements is required. In this case, a Cu substrate, an Fe substrate, or a SUS substrate is suitable.

  Rigidity refers to the degree of difficulty of dimensional change (deformation) with respect to bending and twisting forces or with heat up and down. From this point of view, high rigidity means that a flat substrate remains flat. It means that ability to maintain is high. In other words, the rigidity indicates the degree of difficulty of dimensional change (deformation) with respect to bending or twisting force. That is, high rigidity indicates that the flat substrate is excellent in ability to keep flat.

  However, the collective printed circuit board 100 of the present invention can be applied to other than the camera module. In the drawings, the same or similar components are denoted by the same or similar reference numerals.

=== Aggregate Printed Circuit Board 100 According to the Present Embodiment ===
The collective printed circuit board 100 according to the present embodiment will be described with reference to FIGS. 1A to 1D, 2, 3, 4, 5A to 5P, 10A, and 10B.

  Here, in FIGS. 1A to 1D, 2, 3, 4, and 5A to 5P, the thickness direction of the printed wiring board 101 is defined as the Z direction, and from the front of the page to the back in the plane orthogonal to the Z axis. A direction toward the Y direction is a Y direction, and a direction orthogonal to the Y axis and the Z axis is an X direction.

<< Configuration of Collective Printed Circuit Board 100 >>
The collective printed board 100 is a board in which a plurality of printed wiring boards 101 are connected. The plurality of connected printed wiring boards 101 are separated into individual printed wiring boards 101 by dicing the collective printed circuit board 100. Here, in the collective printed circuit board 100, an area in which electronic components are provided is an arrangement area, and a space between adjacent arrangement areas is a dicing area.

  Here, when the conventional collective printed circuit board 1000 is diced as shown in FIG. 10A, burrs are generated at the end of the printed wiring board 1001 as shown in FIG. 10B. In the printed wiring board 1001, copper is used for the metal core substrate 1100 in order to improve conductivity and thermal conductivity. However, a metal material such as copper having high electrical conductivity and thermal conductivity tends to generate burrs when diced as described above. Here, it is conceivable to use a metal material that hardly generates burrs during dicing for the metal core substrate 1100, but such a metal material has low electrical conductivity and thermal conductivity. Therefore, the collective printed circuit board 100 according to the present embodiment has a structure in which burrs are not easily generated when dicing, and rigidity, conductivity, and thermal conductivity are suppressed.

  As shown in FIGS. 1A and 1C, such a collective printed circuit board 100 includes at least a metal core substrate 110, an insulating layer 120, a conductive pattern 130, and a solder resist layer 140. .

  The metal core substrate 110 is a plate-like member made of a plurality of metal materials, as will be described later, and imparts rigidity to the printed wiring board 101. The metal core substrate 110 is used as, for example, a ground or a ground electrode. The thickness of the metal core substrate 110 is, for example, 250 μm or less, 210 μm, 160 μm, and 120 μm.

  The metal core substrate 110 includes a metal layer 111 formed including a first metal material and a plating layer 112 stacked on the metal layer 111 with a second metal material different from the first metal material. Here, in the metal layer 111, an area corresponding to the arrangement area in the collective printed circuit board 100 is referred to as a plating area, and an area corresponding to the dicing area in the collective printed circuit board 100 is referred to as an exposed area.

  The plating layer 112 is laminated on the upper surface (+ Z direction side) first main surface 111A on the paper surface and the lower surface (−Z direction side) second main surface 111B on the paper surface in the plating region of the metal layer 111. Yes. Furthermore, the plating layer 112 is not formed in the exposed region (dicing line region) of the metal layer 111. Thereby, when the collective printed circuit board 100 is diced, the portion provided with the plating layer 112 is not diced, so that no burrs of the plating layer 112 occur. Furthermore, it is desirable that the plating layer 112 be 50 μm or more inside from the dicing area in the printed wiring board 101 when diced.

  The plated layer 112 preferably has a polycrystalline structure so that irregularities are formed on the surface thereof. Thereby, the adhesiveness of the insulating layer 120 laminated | stacked on the plating layer 112 and the plating layer 112 improves. The improvement in adhesion between the plating layer 112 and the insulating layer 120 will be described in detail later.

  The first metal material that forms the metal layer 111 is, for example, stainless steel, and the second metal material that forms the plating layer 112 is, for example, copper. By covering the metal layer 111 with a metal (plating layer 112) having better conductivity and thermal conductivity than the metal layer 111, the rigidity of the collective printed circuit board 100 is not lowered, and the conductivity and thermal conductivity are reduced. The aggregate printed circuit board 100 can be generated without lowering. Further, since the second metal material forming the plated layer 112 is the same metal material as the conductive material such as the via 133, connection reliability can be improved. The printed wiring board 101 produced by dicing the collective printed circuit board 100 with the metal layer 111 having such a configuration has a higher rigidity than a metal core board made of only the second metal material, and thus has flatness. Can be maintained. Furthermore, since it has high electrical conductivity and thermal conductivity, the metal core substrate 110 can improve the function as a ground and the function as a heat radiating member as compared with the metal core substrate made of only the first metal material.

  Here, the stainless steel is, for example, an alloy steel containing iron (Fe) as a main component (50% or more) and 10.5% or more of chromium (Cr). Further, it is stainless steel, stainless steel, stainless steel or the like. Further, based on the metal structure, it is mainly classified into five categories: martensitic stainless steel, ferritic stainless steel, austenitic stainless steel, austenitic / ferritic duplex stainless steel or precipitation hardening stainless steel. Furthermore, in the Vickers hardness (unit: HV), the martensite type shows 615, the ferrite type shows 183, the austenite type shows 187, the precipitation hardened stainless steel shows 375, both of which are higher in hardness than copper. Indicates.

  In addition, compared to stainless steel as the first metal material, there are harder metal materials, but stainless steel is easier to obtain, easier to process, and less expensive than other metal materials. One of the most suitable metal materials for use. That is, stainless steel is preferable as the first metal material. Hereinafter, in all Examples, it explains as using stainless steel for the 1st metal material.

  1D, the planar structure of the collective printed circuit board 100 will be described. In FIG. 1D, a metal core substrate 111 made of stainless steel and Cu plating is provided substantially over the entire area of the collective printed circuit board 100. Four rectangles indicated by dotted lines are portions that become the printed wiring board (unit substrate) 101, and are arranged in a matrix in the vertical and horizontal directions (X direction and Y direction). In addition, dicing lines are formed in a lattice shape between two adjacent unit substrates 101, and the solid lines in the vertical and horizontal directions (Y direction) are dicing line regions extending in the vertical and horizontal directions. is there. A vertical and horizontal (X direction and Y direction) dicing line indicated by a one-dot difference line is a portion through which a center of a blade (not shown) of a dicing apparatus (not shown) passes. If the blade width is set to be narrower than the width of the dicing line area, the exposed area of the first metal material from which the plating layer 112 has been removed is diced without cutting the plating layer 112 by cutting with a blade. be able to. Here, since the first metal material exists over the entire area, the blade always cuts the first metal material.

  Next, a collective printed circuit board 100 having another structure will be described with reference to FIG. 1B. Four rectangles indicated by dotted lines are portions that become the unit substrate 101 and are arranged in a matrix in the vertical and horizontal directions (X direction and Y direction). Further, a bridge 102 is disposed between two adjacent unit substrates 101. Here, two bridges 102 are provided so as to connect between the opposing sides. As described above, dicing lines are formed in a lattice pattern, and the solid lines in the vertical and horizontal directions (Y direction) are dicing line regions extending in the vertical and horizontal directions. A vertical and horizontal (X direction and Y direction) dicing line indicated by a one-dot difference line is a portion through which the center of the blade of the dicing apparatus passes. If the blade width is set narrower than the width of the dicing line region, the exposed region where the plating layer 112 is removed and the first metal material is exposed is formed on the bridge, and the blade cuts the plating 112. Dicing can be performed without any problem. Here, unlike FIG. 1D, since a slit is formed between the bridges, the amount of cutting of the first metal material can be greatly reduced.

  In both FIG. 1B and FIG. 1D, as shown in FIG. 1C, the exposed region is formed slightly wider on the inside than the region cut by the blade (the width is formed wider), so that the blade The plating layer 112 is not scraped.

  Here, the thickness of the metal layer 111 and the plating layer 112 will be described with reference to FIG. FIG. 2 shows a metal layer 111 (stainless steel) and a plating layer 112 (copper) in a rectangular printed wiring board 101 formed including a 120 μm metal core substrate 110 and having a size of 17.8 mm × 8.5 mm. The relationship between the thickness ratio and the amount of deformation of the printed wiring board 101 is shown. The horizontal axis of the graph shown in FIG. 2 indicates the ratio of the thickness of the plating layer 112 to the thickness of the metal layer 111, and the vertical axis of the graph indicates the deformation amount of the printed wiring board 101. As shown in FIG. 2, as the proportion of the metal layer 111 having a relatively large elastic modulus increases or as the proportion of the plating layer 112 having a relatively small elastic modulus decreases, the amount of deformation of the printed wiring board 101 increases. It turns out that it decreases. In other words, it can be seen that the rigidity of the printed wiring board 101 is increased.

  For this reason, in the collective printed circuit board according to the present embodiment, it is preferable that the thickness of the plating layer 112 is thinner than the thickness of the metal layer 111. For example, when the thickness of the metal core substrate 110 is 120 μm, the thickness of the metal layer 111 is preferably greater than 60 μm, and the thickness of the plating layer 112 is preferably less than 60 μm. In other words, it is preferable that the thickness TA of the metal A satisfies 2TA / TB <1 in relation to the thickness TB of the metal B. By adopting such a metal core substrate 110, the rigidity of the printed wiring board 101 can be improved as compared with a substrate having the same thickness made of only the second metal material. Further, since the function of the printed wiring board 101 is not affected as long as at least TA / TB <1 is experimentally satisfied, such a thickness relationship may be used.

  A suitable combination of the first metal material and the second metal material is the above-described stainless steel and copper, but is not limited thereto. Specifically, for example, a combination of other metal materials satisfying the conditions described later may be used, such as a combination of any one of “iron” and “nickel” and “aluminum”. However, the first metal material and the second metal material are desirably metals that are difficult to diffuse.

  In addition, the conductivity of the plating layer 112 is higher than the conductivity of the metal layer 111, and the thermal conductivity of the plating layer 112 is higher than the thermal conductivity of the metal layer 111. As described above, the combination of the first metal material and the second metal material satisfies this relationship. However, any one of the electrical conductivity and thermal conductivity in the plating layer 112 may be higher than the corresponding physical property value in the metal layer 111.

  In addition, the metal core substrate 110 may have a metal intervening layer (not shown) as an intermediate metal between the metal layer 111 and the plating layer 112. Thereby, the adhesion between the metal layer 111 and the plating layer 112 is enhanced. The third metal material contained in the metal intervening layer is selected from at least one of, for example, nickel, palladium, titanium, tungsten, chromium, cobalt, or tin. Further, the third metal material may diffuse into the first metal material and the second metal material, for example, tin.

  In the present embodiment, the metal intervening layer is a thin film of less than 1 μm, and hardly affects the mechanical properties of the metal core substrate 110. In addition, as the third metal material, two or more kinds of the metal materials described above may be selected.

  The insulating layer 120 is formed on the surface of the metal core substrate 110. The insulating layer 120 is made of, for example, epoxy resin, polyimide, or bismaleimide triazine resin. Glass fibers are provided in the resin. Moreover, you may contain fillers, such as aluminum oxide or silicon dioxide, instead of this glass fiber. Furthermore, both glass fiber and filler may be mixed. The resin is a so-called thermosetting synthetic resin.

  As shown in FIGS. 1A and 1C, the insulating layer 120 is formed of two layers of the first insulating layer 121 and the second insulating layer 122, but the number of layers of the insulating layer 120 may be changed as appropriate. .

  The conductive pattern 130 is formed on the insulating layer 120 and insulated. The material of the conductive pattern 130 is preferably a second metal material or a material having mechanical properties close to those of the second metal material. For example, when the plating layer 112 includes copper, the most suitable material for the conductive pattern 130 is copper. For example, the conductive pattern 130 is formed in the printed circuit board region 101, which is not overlapped with the exposed region in a plan view so as to facilitate dicing and not cause burrs.

  As shown in FIGS. 1A and 1C, the conductive pattern 130 is shown to include two layers of the first conductive pattern 131 and the second conductive pattern 132. The number of the conductive patterns 130 included in the conductive pattern 130 is as follows. It may be changed as appropriate.

  As clearly shown in the manufacturing method described later, when the first conductive pattern 131 is formed of copper, a plated layer 112 mainly composed of copper or copper is formed on both surfaces of the metal layer 111. The GND wiring in the first conductive pattern 131 is mechanically and electrically connected to the plating layer 112 through a through hole or a via. In other words, the first conductive pattern 131 is so-called substrate ground.

  The solder resist layer 140 is an insulating film that protects the circuit pattern formed on the printed wiring board 101, and is formed on the surface of the insulating layer 120. The solder resist layer 140 is made of, for example, a thermosetting epoxy resin. In order to facilitate dicing, the solder resist layer 140 on one side corresponding to the exposed region of the metal layer 111 is preferably removed. On the other hand, it is preferable that the solder resist layer 140 on the other side is not removed so that the collective printed circuit board 100 can be stably placed when dicing.

  In this embodiment, the printed wiring board 101 does not include a built-in component, but the printed wiring board 101 may include a built-in component.

<< Rigidity improvement by improving adhesion between plating layer 112 and insulating layer 120 >>
With reference to FIG. 3, the improvement in the rigidity of the printed wiring board 101 by improving the adhesion between the plating layer 112 and the insulating layer 120 will be described.

  The plating layer 112 has a small crystal structure and a polycrystalline structure. Further, since it grows in the Z direction, it has a columnar structure. Therefore, the surface exhibits a fine rough surface and high adhesion. Furthermore, since the plating layer 112 has a polycrystalline structure, when etched, the grain boundaries are further etched, and the roughness can be further increased.

  Further, by filling the insulating layer 120 with a filler, the rigidity of the printed wiring board 101 can be further increased. The filler is a granular, crushed, short fiber (needle) or woven fiber sheet filler. When the filler is mixed in the resin, the rigidity of the printed wiring board 101 increases. The granular, crushed and short fiber fillers are, for example, silicon oxide film, aluminum oxide, acicular glass fibers, acicular carbon and graphite fibers.

  Further, instead of the filler described above, as shown in FIGS. 3A and 3B, reinforcing reinforcing fibers woven with reinforcing fibers such as carbon fibers or glass fibers in the insulating layer 120 are used. A sheet 123 may be provided. The reinforcing fiber sheet 123 is woven thinly like a cloth two-dimensionally (planar) with respect to the plating layer 112. In the reinforcing fiber sheet 123, for example, a large number of reinforcing fibers 123A provided in the horizontal direction (X direction) on the paper surface and reinforcing fibers 123B provided in the vertical direction (Y direction) on the paper surface are arranged and woven so as to be alternately sewn. Since this sheet is solidified integrally with the resin of the insulating layer 120, and further, the insulating layer is brought into close contact with the unevenness of the plated layer 112 by the anchor effect, so that the rigidity of the printed wiring board is enhanced. The rigidity can be further increased by using a reinforcing fiber such as carbon instead of the glass reinforcing fiber sheet 123.

<< Improvement of contact between metal layer 111 and via 133 >>
As shown in FIG. 4, when the conductive pattern 130 is connected to the metal core substrate 110 via the via 133, the printed wiring board 101 is improved by improving the contact property between the via 133 and the metal core substrate 110. The rigidity and the low resistance of the contact portion can be improved. In general, in order to form the via 133, the insulating layer 120 is cured, laser processing for forming the via 133, and processing using an etching solution are performed. In this process, the surface of the metal layer 111 is oxidized. A film is produced. By forming the oxide film in this way, if the via 133 is plated, the resistance value is increased due to an increase in resistance value, ion migration, etc., and the characteristics of the printed wiring board 101 are affected. The rigidity of the wiring board 101 is also affected.

  In order to solve this problem, as shown in FIG. 4, the collective printed wiring board 100 has a structure in which the plated layer 112 in the via 133 is removed to expose the metal layer 111 and the via 133 is formed there. You may do it. At the bottom of the via 133 (the surface of the metal layer 111), a flat crystal structure that extends in the XY plane is exposed. Thereby, since ions and water are not easily trapped, formation of an oxide film can be prevented, so that good adhesion can be obtained.

  When the printed wiring board 101 generated from the collective printed circuit board 100 according to the present embodiment is applied to a camera module, an image sensor as a semiconductor element is mounted on the printed wiring board 101. Further, a lens unit, an autofocus actuator, a filter unit, and an optical package for fixing and arranging the lens unit, the actuator, and the filter unit are disposed around the imaging element. There is also a high resolution type in which a plurality of the camera modules are arranged. When the printed wiring board 101 according to the present embodiment is employed, since the rigidity is high and the flatness of the printed wiring board 101 is high, optical adjustment becomes easy. Further, unlike the printed wiring board 101 using ceramic as a core substrate, workability is improved because it is difficult to break.

<< Manufacturing Process of Collective Printed Circuit Board 100 >>
The manufacturing process of the collective printed circuit board 100 will be described as follows with reference to FIGS. 1C and 5A to 5J.

  First, in order to form the metal core substrate 110, a metal layer 111 is prepared as shown in FIG. 5A. When the printed wiring board 101 includes a built-in component, a hole is formed in the metal layer 111, the built-in component is inserted into the hole, and the hole is sealed with resin.

  Subsequently, as shown in FIG. 5B, a through hole 111C is formed in a portion corresponding to the through hole of the circuit board. The through hole 111C is formed by machining such as punching, etching, laser processing, or the like. Subsequently, as shown in FIG. 5C, resin sheets 111D and 111E for plating are formed and patterned. Here, the resin sheet is patterned so as to cover the through hole 111C and at the same time, the resin sheet 111E is provided also in a portion corresponding to the dicing line. This is possible by photoetching. Thereafter, it is poured into a plating solution to form a plating layer 112. Thereafter, when the resin sheets 111D and 111E are removed, the plating layer 112 is not formed in the portion corresponding to the dicing line region, and an exposed region is formed. A plating 112 is formed in the arrangement region (see FIG. 5D). As shown in FIG. 5I, a plating film 112 was formed on the entire surface of both surfaces of the metal layer 111, and then the plating layer 112 corresponding to the through hole 111C and the exposed region was removed as shown in FIG. 5J. Later, the through hole H may be formed by machining or laser processing.

  Subsequently, as shown in FIG. 5E, the first insulating layer 121 is formed on the surface of the metal layer 111 including the plating layer 112, and the holes 160 and through holes are formed in the first insulating layer 121 by, for example, etching or laser processing. A hole 134 (see FIG. 5E) is formed. The hole 160 is a contact hole with the metal layer, and the through hole 134 is smaller than the through hole hole 134A and is a hole covered with an insulating layer 120 on the inner wall.

  Then, as shown in FIG. 5F, a metal coating layer 131A is formed by plating so as to fill the inside of the through hole 134 and the hole 160 and cover the surface of the first insulating layer 121. Note that the metal coating layer 131A to be the conductive pattern 130 is generally copper.

  Subsequently, as shown in FIG. 5G, the metal coating layer 131A formed on both surfaces is patterned by, for example, wet etching to form the first conductive pattern 131. The first conductive pattern 131 constitutes a wiring or an electrode. Further, in the first conductive pattern 131, wirings or electrodes that require substrate grounding are electrically connected to the metal layer 111 and the plating layer 112 through the holes 160. The hole 160 is, for example, a via.

  Further, the second insulating layer 122 is formed so as to cover the surface and the back surface of the substrate 100 and the surface of the first conductive pattern 131. Then, a hole 170 is formed in the second insulating layer 122 by an etching process or a laser processing method. Then, a second metal coating layer (not shown) is formed by a plating method so as to fill the inside of the hole 170 and further to cover the entire surface of the second insulating layer 122. Then, as shown in FIG. 5H, the second conductive pattern 132 is formed by patterning the second metal coating layer.

  Next, a solder resist layer 140 is formed on the surface of the substrate. Specifically, the solder resist layer 140 is formed so as to cover the surfaces of the second conductive pattern 132 and the second insulating layer 122, and the solder resist layer 140 is partially removed by an etching process (development process). The second conductive pattern 132 is exposed. The second conductive pattern 132 exposed from the solder resist layer 140 becomes an electrode for mounting a component to be described later, a pad electrode for wire bonding, or the like.

  Thereafter, as shown in FIG. 1C, the completed collective printed circuit board 100 is cut and divided into individual pieces, for example, by a dicing apparatus. After that, the separated printed wiring board 101 is mounted with, for example, a camera component such as an image sensor, here a semiconductor chip or a passive component. 5H indicates the thickness direction of the substrate to be diced, and is scanned in a grid pattern as shown in FIGS. 1B and 1D.

  As described above, in this embodiment, the strength of the metal core substrate 110 is higher than that of the same thickness substrate made of only the second metal material (for example, copper). Can be obtained.

  This is because by using a metal material having hardness higher than copper for the metal layer 111, a substrate having strength, rigidity, and flatness can be obtained even if it is thin. In particular, the use of stainless steel is preferable because it has higher rigidity than copper and can be manufactured at a relatively low cost.

  In addition, the metal core substrate 110 can have higher conductivity than a substrate made of only the first metal material (for example, stainless steel). Therefore, there is little resistance and heat generation of the substrate itself can be suppressed.

  In addition, since the metal core substrate 110 having a higher thermal conductivity than that of the substrate made of only the first metal material can be obtained, the printed wiring board has better heat dissipation than the substrate made of only the first metal material. 101 can be obtained.

  Further, a metal material having a higher elastic modulus than copper is used for the metal layer 111, and the plated layer 112 is not formed in the exposed region of the metal layer 111. Thereby, the rigidity of the printed wiring board 101 is ensured and no burrs are generated when the exposed area is diced.

=== Other Embodiments ===
Other embodiments will be described as follows with reference to FIGS. 6, 7A, 7B, 7C, 8 and 9. FIG. FIG. 6 is a cross-sectional view schematically showing the collective printed circuit board 200 in which the plating layer 212 is laminated on the first side surface 211A of the metal layer 211 according to another embodiment. FIG. 7A is a cross-sectional view schematically showing a collective printed circuit board 300 in which a part of the metal layer 311 according to another embodiment is formed thin. FIG. 7B is an enlarged cross-sectional view of the metal layer 311 having a curved surface on one side in the collective printed circuit board 300 in which a part of the metal layer 311 according to another embodiment is formed thin. FIG. 7C is an enlarged cross-sectional view of the metal layer 311 having curved surfaces on both sides in the collective printed circuit board 300 in which a part of the metal layer 311 according to another embodiment is formed thin. FIG. 8 is a cross-sectional view schematically illustrating a collective printed circuit board 400 in which a plating layer 412 is stacked on the second side surface 411A of the metal layer 411 according to another embodiment. FIG. 9 is a cross-sectional view schematically showing a collective printed circuit board 500 in which a plurality of metal core substrates 510 according to other embodiments are formed with insulating layers 520 interposed therebetween.

  In the following description, only differences from the embodiment shown in FIGS. 1A and 1C will be described. In FIGS. 6 to 9, only components different from the embodiment shown in FIGS. Is granted.

  6 to 9, the thickness direction of the printed wiring boards 201 to 501 is defined as the Z direction, and the direction from the front of the page to the back in the plane orthogonal to the Z axis is the Y direction, and the Y axis and the Z axis The direction orthogonal to is the X direction.

  The collective printed circuit board 200 according to the embodiment shown in FIG. 6 is obtained by forming a plating layer 212 on the inner wall of the through hole 234 of the metal layer 211. In FIG. 5B, this can be achieved by omitting the sheet 111D that closes the through hole 111C and performing plating. Since the inner wall of the through hole 234 is covered with the conductive film, the conductivity and thermal conductivity can be improved. Further, since the inner wall of the through hole is also a plated film, the adhesion with the insulating resin is improved.

  Subsequently, as shown in FIG. 7A, a cut portion indicating the exposed region of the metal layer 311 may be formed thin in the Z direction. Thereby, while the quantity of the metal material of the metal layer 311 can be reduced, generation | occurrence | production of a burr | flash can be suppressed more when dicing the cutting part 311A. Such a collective printed circuit board 300 is manufactured by removing the plating layer 312 and etching it so that the cut portion 311A becomes thinner in a situation where the plating layers 312 are laminated on both surfaces of the metal layer 311.

  Further, in this case, as shown in FIG. 7B, one surface in the Z direction in the cut portion 311A may be formed by etching so as to have a curved surface. Further, as shown in FIG. 7C, the both sides in the Z direction in the cut portion 311A may be formed by a curved surface by etching. Thereby, even if a burr | flash generate | occur | produces with the suppression of a burr | flash, since the front-end | tip of the burr | flash is located in a recessed part, a short circuit can be suppressed.

  The collective printed circuit board 400 according to the embodiment shown in FIG. 8 is obtained by forming a plating layer 412 on the side wall 411C of the recess 311B shown in FIG. 7A. By increasing the lamination area of the plating layer 412 with respect to the metal layer 411, the conductivity and thermal conductivity of the collective printed circuit board 400 can be increased.

  As shown in FIG. 9, the metal core substrate 510 may be configured to be laminated via an insulating resin. Thus, if a thin element is built by forming a cavity in the upper metal core layer, or if both metal core layers are made thin, it can be used as a fine wiring layer or electrode.

=== Summary ===
As described above, the collective printed circuit board 100 is exposed to the metal layer 111 and the corresponding metal layer 111 between adjacent placement areas in the collective printed circuit board 100 having a plurality of placement areas where a plurality of unit boards are provided. A plating layer 112 formed on the first main surface 111A of the metal layer 111 and on the second main surface 111B of the metal layer 111 opposite to the first main surface 111A so as to form a region; , An insulating layer 120 formed to cover the surface of the metal core substrate 110, and a conductive pattern 130 formed on the insulating layer 120 corresponding to the arrangement region. According to such an embodiment, the metal core substrate corresponding to the dicing region is an exposed region in which the plating layer is omitted, so that burrs during dicing can be suppressed. Thereby, the collective printed circuit board 100 with higher quality can be provided. In particular, since Cu is soft and easily generates burrs, generation of burrs can be suppressed by omitting them in the dicing region.

  Further, the metal layer 111 of the collective printed circuit board 100 is made of a metal material mainly composed of iron or a metal material mainly composed of aluminum. According to this embodiment, since the collective printed circuit board 100 can be provided with rigidity higher than that of copper often used as the metal layer 111, it is possible to maintain flatness.

  Further, the plating layers 212 and 412 of the collective printed circuit boards 200 and 400 are on the first side surface (third main surface) of the metal layers 211 and 411 formed perpendicular to the first main surface 111A and the second main surface 111B. Further formed. According to this embodiment, by increasing the lamination area of the plating layers 212 and 412 with respect to the metal layers 211 and 411, the conductivity and thermal conductivity of the collective printed circuit board 100 can be increased.

  Further, the plating layer 112 of the collective printed circuit board 100 is made of a metal material whose main material is copper. According to this embodiment, since it has higher electrical conductivity and thermal conductivity than, for example, copper forming the metal layer 111, the function as a ground and the function as a heat dissipation member in the metal core substrate 110 can be improved.

  In addition, the plating layer 112 of the collective printed circuit board 100 has a polycrystalline structure, and the surface of the plating layer 112 that contacts the insulating layer 120 has irregularities for improving the adhesion between the plating layer 112 and the insulating layer 120. According to this embodiment, the adhesion between the plating layer 112 and the insulating layer 120 can be improved.

  In addition, a reinforcing fiber sheet 123 made of reinforcing fibers is embedded in the insulating layer 120 of the collective printed circuit board 100. According to this embodiment, the rigidity of the collective printed circuit board 100 can be improved by improving the adhesion with the insulating resin.

  Further, in the metal layer 311 of the collective printed circuit board 300, the cut portion 311A (first metal portion) of the metal layer 311 in the exposed region is formed thinner than the metal layer 311 other than the exposed region. According to this embodiment, the amount of burrs generated can be suppressed or the length of burrs can be shortened. Furthermore, the load on the blade can also be suppressed.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this. The material, shape, and arrangement of each member described above are merely embodiments for carrying out the present invention, and various changes can be made without departing from the spirit of the invention.

100, 200, 300, 400, 500 Collected printed circuit board 101, 501 Printed wiring board 110, 510 Metal core board 111, 211, 311, 411 Metal layer 111A First main surface 111B Second main surface 112, 212, 312, 412 Plating layer 120 Insulating layer 123 Reinforcing fiber sheet 130 Conductive pattern 140 Solder resist layer

Claims (15)

In a collective printed circuit board having a plurality of arrangement areas each provided with a plurality of unit boards and an exposed area that is an area between the adjacent arrangement areas ,
A first main surface and a second main surface opposite to the first main surface, wherein at least one of the first main surface and the second main surface extends from the arrangement region to the exposed region. A metal layer that is flat ;
A plating layer provided in contact with the first main surface and the second main surface of the metal layer so as not to overlap the exposed region ;
A metal core substrate having
An insulating layer formed to cover the surface of the metal core substrate;
A conductive pattern formed on the insulating layer corresponding to the arrangement region;
A collective printed circuit board comprising: The collective printed circuit board according to claim 1, wherein the exposed region is a dicing region for separating the plurality of adjacent arrangement regions. The collective printed circuit board according to claim 2, wherein a bridge is provided in a corresponding region between the plurality of adjacent unit boards. The collective printed circuit board according to any one of claims 1 to 3, wherein the metal layer is made of a metal material mainly made of iron or a metal material mainly made of aluminum. The collective printed circuit board according to any one of claims 1 to 4, wherein the plating layer is made of a metal material mainly composed of copper. The said plating layer is further formed on the 3rd main surface of the said metal layer formed perpendicularly | vertically with the said 1st main surface and the said 2nd main surface. The Claim 4 or Claim 5 characterized by the above-mentioned. The collective printed circuit board according to any one of the above. The plating layer has a polycrystalline structure,
7. The surface according to claim 1, wherein a surface of the plating layer that is in contact with the insulating layer has irregularities for improving adhesion between the plating layer and the insulating layer. Assembly printed circuit board. Collection printed circuit board according to claim 1 in the cross section of the area where the metal layer toward the exposed region of the arrangement region is provided, the thickness of the metal layer, which is a constant. The collective printed circuit board according to any one of claims 1 to 8, wherein a plurality of the metal core substrates are laminated via an insulating resin. Collection printed circuit board according to claim 1 wherein the thickness of the metal layer in the exposed area, characterized in that it is formed thinner than the thickness of the metal layer other than the exposed region. A plurality of arrangement areas each provided with a plurality of unit substrates , and an exposed area that is an area between the adjacent arrangement areas ;
A first main surface and a second main surface opposite to the first main surface, wherein at least one of the first main surface and the second main surface extends from the arrangement region to the exposed region. A metal layer that is flat ;
By forming a resin sheet in the exposed region, a plating layer provided so as to be in contact with the first main surface and the second main surface of the metal layer so as not to overlap the exposed region ;
A metal core substrate having
An insulating layer formed to cover the surface of the metal core substrate;
A conductive pattern formed on the insulating layer corresponding to the arrangement region;
Prepare a printed circuit board with
The exposed region between the adjacent plurality of placement areas are mechanically separated, a method for manufacturing a printed wiring board, characterized in that to produce a single printed circuit board. The method for manufacturing a printed wiring board according to claim 11, wherein a bridge is provided in a corresponding region between the plurality of adjacent unit substrates. The metal layer is made of a metal material mainly made of iron or a metal material made mainly of aluminum, and the plated layer is made of a metal material mainly made of copper. Item 13. A method for producing a printed wiring board according to Item 12. The thickness of the metal layer in the exposed region is formed thinner than the thickness of the metal layer other than the exposed region,
14. The mechanical separation between the plurality of adjacent placement regions is performed so that the metal layer in the exposed region is exposed from the printed wiring board. The manufacturing method of the printed wiring board as described in 1 .. The printed wiring according to any one of claims 11 to 14 , wherein the exposed region is mechanically separated by using a dicing apparatus having a blade having a narrower width than the width of the exposed region. A manufacturing method of a board.

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